Rhodomyrtus tomentosa is a large evergreen shrub native to Southeast Asia that has become an invasive species in other tropical and subtropical countries. Introduced to many areas as an ornamental plant, it has spread, forming large, monospecific thickets that displace native flora and fauna. Areas especially affected include Florida, Hawai‘i and French Polynesia.

Introduced to Hawai‘i c.1920 (Degener, 1963 in Langeland and Burks, 1999). By the 1950s was forming impenetrable thickets on Kauai and Hilo (Hosaka and Thistle, 1954 in Langeland and Burks, 1999). Currently on the State of Hawai‘i noxious weed list (Meyer, 1998 in PIER, 2003).

A serious problem on Raiatea, French Polynesia (Meyer, 1998 in PIER, 2003).

Introduced to Florida in the 1920s by the US Department of Agriculture as an ornamental and landscape plant, as well as for its fruit (Gordon and Thomas, 1997 in PIER, 2003). It escaped cultivation soon after and has now spread to 17 counties (Center for Natural Resources, 2003).

Research was conducted at the University of Florida 1998-2000 to describe the ecology and determine effective control methods for this species.

Lifecycle Stages

Flowers abundantly in spring (Langeland and Burks, 1999). In Florida, fruits are ripe in August and September (Possley, pers. comm.).

Uses

Has shown promise as a fire retardant species for use in fire breaks in the Himalayas (Ministry of Environment & Forests, 2003). Is aesthetically pleasing, hence its use as an ornamental and landscaping plant (Center for Natural Resources, 2003). Has sweet edible fruit, which can be made into pies and jams, or used in salads. The fruit is also a food source for birds and mammals (Center for Aquatic and Invasive Plants, 2001).

Habitat Description

Moist and wet forests, bog margins, up to 2400m elevation (Hosaka and Thistle, 1954 in Langeland and Burks, 1999). Able to invade a range of habitats, from pine flatwoods to mangrove marshes (Center for Natural Resources, 2003). Grows in a wide range of soil types, including salty coastal soil, but is sensitive to heavy salt spray (Menninger, 1964 in Langeland and Burks, 1999). Frost-tolerant (Bailey and Bailey, 1976 in Langeland and Burks, 1999). 'Fire-adapted,' is able to resprout prolifically after fire (Center for Aquatic and Invasive Plants, 2001).

Reproduction

Seeds are dispersed by frugivorous birds. Can only spread by seed drop, as it does not spread vegetatively (Center for Aquatic and Invasive Plants, 2001). Has a large amount of seed production and high germination rate (Center for Natural Resources, 2003). Berries usually contain 40-45 seeds (Possley, pers. comm.).

Pathway

Introduced to Florida by US Dept. of Agriculture in 1920s as a landscaping plant, for ornamentation, and for its edible fruit (Center for Natural Resources, 2003).

Invades the understory of native pinelands in Florida, forming dense monoculture thickets that displace native flora and fauna through overcrowding and competition. Has the potential to alter the natural fire regimes of invaded areas (Center for Aquatic and Invasive Plants, 2001).

Management Info

Preventative measures: A Risk Assessment of Rhodomyrtus tomentosa for Hawai‘i and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service. The alien plant screening system is derived from Pheloung et al. (1999) with minor modifications for use in Pacific islands (Daehler et al. 2004). The result is a score of 8 and a recommendation of: \"Likely to cause significant ecological or economic harm in Hawai‘i and on other Pacific Islands as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawai‘i and/or other parts of the world.\"

\r\nIntegrated management: Seedlings can be manually removed. Mature shrubs may be felled using a chainsaw or brush cutter and treating the stumps with a commercial herbicide (Stocker and Possley 2001).

Informations on Rhodomyrtus tomentosa has been recorded for the following locations. Click on the name for additional informations.

Lorem Ipsum

Location

Status

Invasiveness

Occurrence

Source

Details of Rhodomyrtus tomentosa in information

Status

Invasiveness

Arrival date

Occurrence

Source

Introduction

Species notes for this location

Location note

Management notes for this location

Method:

Source:

Start date:

End date:

Impact

Mechanism:

Outcome:

Ecosystem services:

Impact information

Invades the understory of native pinelands in Florida, forming dense monoculture thickets that displace native flora and fauna through overcrowding and competition. Has the potential to alter the natural fire regimes of invaded areas (Center for Aquatic and Invasive Plants, 2001).

Preventative measures: A Risk Assessment of Rhodomyrtus tomentosa for Hawai‘i and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service. The alien plant screening system is derived from Pheloung et al. (1999) with minor modifications for use in Pacific islands (Daehler et al. 2004). The result is a score of 8 and a recommendation of: \"Likely to cause significant ecological or economic harm in Hawai‘i and on other Pacific Islands as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawai‘i and/or other parts of the world.\"

\r\nIntegrated management: Seedlings can be manually removed. Mature shrubs may be felled using a chainsaw or brush cutter and treating the stumps with a commercial herbicide (Stocker and Possley 2001).

Daehler, C.C; Denslow, J.S; Ansari, S and Huang-Chi, K., 2004. A Risk-Assessment System for Screening Out Invasive Pest Plants from Hawaii and Other Pacific Islands. Conservation Biology Volume 18 Issue 2 Page 360.Summary: A study on the use of a screening system to assess proposed plant introductions to Hawaii or other Pacific Islands and to identify high-risk species used in horticulture and forestry which would greatly reduce future pest-plant problems and allow entry of most nonpests.

Possley, J., K. Kitajima and R.K. Stocker. In press. Seasonal allocation of carbohydrates in an invasive Florida shrub: Rhodomyrtus tomentosa. Florida Scientist.Summary: Condensed version of masters thesis includes description of phenology, growth, and carbohydrate allocation of this species in a Florida pine flatwoods. Includes management recommendations.

Stocker, R.K., and Possley, J. 2001. Comparing application methods and herbicides for control of Rhodomyrtus tomentosa. Ecological Restoration 19(1):34-36.Summary: Examination of several common herbicides and three different application methods (foliar spray, hack-and-squirt, and basal bark). Includes management recommendations, black and white photographs, and line drawing.

General information

Alexander, T. 1981. An exotic plant pest. The Palmetto 1(1):2-3.Summary: Discussion of the spread and invasion of this species into Florida s natural areas.

Wagner, W.L., Herbst, D.R. and Sohmer, S.H.� 1990.� Manual of the flowering plants of Hawai i.� Volume 1.� University of Hawaii Press. Summary: History of introduction/spread in Hawaii. Describes origin of common name Isenberg Bush.

Contact

The following 4 contacts offer information an advice on Rhodomyrtus tomentosa

Geographic region: Pacific, Indian OceanEcosystem: Terrestrial Expert in the botany of French Polynesia and the Pacific Islands, and has worked on ecology and biological control of Miconia calvescens in French Polynesia.